Some non-volatile memory devices erase data logically but not physically. Thus, data that has been erased by a user may still be recoverable from the memory device. U.S. Pat. No. 8,130,554, whose disclosure is incorporated herein by reference, describes a method for securely erasing Flash-based memory. A new version of data is received for a logical location of a Flash-based memory. An old version of the data of the logical location is stored in a first physical location in the Flash-based memory. The old version of the data is caused to be subject to an obscure operation. The old version of the data is caused to be stored in a second physical location in the Flash-based memory.
U.S. Patent Application Publication 2010/0138619, whose disclosure is incorporated herein by reference, describes a method in which one or more target files are securely erased form a host storage medium such as a disk by overwriting the target files not just with “0”s, “1”s and/or random data, but also by overwriting them with portions of other selected, innocuous files found on the same medium. By booting the host using a secondary, preferably external mechanism before the host operating system is allowed to load, logging of file accesses and process execution by the host OS is circumvented. Post-replacement fragmentation and defragmentation may also be used to further reduce the detectability of the erasure, and the success of the process may be evaluated using statistical analysis.
U.S. Pat. No. 8,261,005, whose disclosure is incorporated herein by reference, describes an apparatus, system, and method for managing data with an empty data segment directive at the storage device. The apparatus, system, and method for managing data include a write request receiver module and a data segment token storage module. The write request receiver module receives a storage request from a requesting device. The storage request includes a request to store a data segment in a storage device. The data segment includes a series of repeated, identical characters or a series of repeated, identical character strings. The data segment token storage module stores a data segment token in the storage device. The data segment token includes at least a data segment identifier and a data segment length. The data segment token is substantially free of data from the data segment.